The present invention relates to a method and apparatus for removing slag cakes from synthesizing gas reactors.
The state of the art of manufactured gas may be ascertained by reference to the Kirk-Othmer "Encyclopedia of Chemical Technology", 2nd Edition, Vol. 10 (1966), pp. 353-442, particularly pages 426-430, in Ullmanns Encyklopedie der technischen Chemie, Vol. 16 (1965), pp. 626-628, in Chemical and Process Engineering, August 1970, pp. 53-57 or in Chemiker-Zeitung 96, pp. 123-134(1972) which disclose processes and apparatus operating at elevated pressure. These processes and apparatus are incorporated herein.
Mostly carbon monoxide and hydrogen are manufactured in synthesizing gas reactors by partially oxidizing heavy oil under pressure with oxygen. A slag deposits in the lower part of the reactor and must be periodically removed. Ordinarily this is done by stopping reactor operation and cooling, whereupon the reactor is opened at the bottom, the uncovered part of the ceramic lining is removed, and then the slag. Thereupon the reactor is sealed again by recasting the removed part of the lining and closing the reactor. The newly cast seal must be dried and annealed. This method requires inoperativeness of about 12 days, drying and annealing alone requiring about 7 days.
Several methods for removing slag from hot vessels or reactors are known. Thus tapping during operation is known in iron working technology. But reactors operating at high gas pressure will not allow opening during operation.
The Shell pressure gassifier is such a high gas pressure reactor and it is illustrated in Chemical and Process Engineering ibid, FIG. 4, p. 54, and the performance data are given on pages 55-57.
Even if the reactor were shut down and the pressure decreased, tapping through the ceramic refractory lining would be inapplicable because the slag inevitably would penetrate between the refractory layers and destroy this refractory. Furthermore, at ordinary reactor temperatures, only a layer of a few centimeters is liquid at the surface of the slag cake, the lower part already cooling and being solidified. Admixtures for liquefying the entire slag entail the risk that the ceramic refractory material too will be decomposed and destroyed.
It is further known how to cut substances of high melting points such as concrete by means of an oxygen core lance. However, the use of an oxygen core lance to melt slag cakes from synthesizing gas reactors so far is not known.